Free Photo Silhouette Of Bird Flying Outdoors Freedom Raptor. The shape of the wing is important in determining the flight capabilities of a bird Different shapes correspond to different trade offs between advantages such as speed low energy use and maneuverability Two important parameters are the aspect ratio and wing loading Aspect ratio is the ratio of wingspan to the mean of its chord or the square of the wingspan divided by wing area Wing loading is the ratio of weight to wing area.

Another ground upwards theory argues the evolution of flight was initially driven by competitive displays and fighting displays required longer feathers and longer stronger forelimbs many modern birds use their wings as weapons and downward blows have a similar action to that of flapping flight Many of the Archaeopteryx fossils come from marine sediments and it has been suggested that wings may have helped the birds run over water in the manner of the Jesus Christ lizard common basilisk